feat(from_curl): import HTTP spec from curl command line (#186)

* feat(from_curl): import HTTP spec from curl command line

Curl is a standard way of specifying the API requests. It is a common
format in scripts, API docs and browsers supports Copy as cURL in the
network tools as well.

This commit adds

1. shlex-lua source code into project
2. code parsing the curl command line and generating the Request table
3. code appending the Request into current buffer

* Split the curl parsing into new module

use nvim_put to print the HTTP spec

* Improve curl command line parsing

1. supports short and long options now
2. supports HTTP version specification
3. now is omited if not specified on a command line

* Include documentation

* Problem: url can appear everywhere in a command line

Solution: when not parsing any particular command, consider the first
argument matching `^http(s)?://` as url. This fixes an export from
Firefox for example.

* Problem: --data-raw not supported

And it is used by Mozilla Firefox cURL export. According man curl
the default content encoding is application/x-www-form-urlencoded, so
read this too.

* Support --json

This is neat shortcut for

```
--data [arg]
--header "Content-Type: application/json"
--header "Accept: application/json"
```

* Problem: header parsing was broken

Solution: add a proper cut method - similar to strings.Cut from Go,
which splits the string into two parts and use remove_extra_space
allowing form `--header 'Key: Value` to become `"Key"`, `"Value"`.

* Problem: support http/https scheme only

Solution: match all valid schemes if they ends with :// - curl supports
more than HTTP anyway.

* refactor(from-curl)

* chore(cleanup)

* feat(from-curl): multi-line curl support

* refactor(from-curl): put original curl command

---------

Co-authored-by: Marco Kellershoff <[email protected]>

docs/docs/usage/public-methods.md

@@ -40,6 +40,12 @@ It's default contents can be configured via the
 `require('kulala').copy()` copies the current request
 (as cURL command) to the clipboard.
 
+### from_curl
+
+`require('kulala').from_curl()` parse the cURL command from the clipboard and
+write the HTTP spec into current buffer. It is useful for importing requests
+from other tools like browsers.
+
 ### close
 
 `require('kulala').close()` closes the kulala window and also the current buffer.

lua/kulala/init.lua

@@ -37,6 +37,10 @@ M.show_stats = function()
   UI:show_stats()
 end
 
+M.from_curl = function()
+  UI:from_curl()
+end
+
 M.version = function()
   local neovim_version = vim.fn.execute("version") or "Unknown"
   Logger.info("Kulala version: " .. GLOBALS.VERSION .. "\n\n" .. "Neovim version: " .. neovim_version)

lua/kulala/lib/shlex/init.lua

@@ -0,0 +1,336 @@
+-- All credits due to the original author of this code
+-- https://github.com/BodneyC/shlex-lua/
+--
+-- It has been modified to work with Neovim and removed some continue statements
+-- that could be also breaks, idk about performance but it works and
+-- doesn't break stylua.
+--
+-- The original code has no license, so I'm assuming it's public domain
+-- The author states that:
+--
+-- It's a couple files you can drop into your project
+-- (or even your Neovim config (which is why I wrote it))
+-- if you need to parse a shell command.
+
+local M = {}
+
+local function some(o)
+  return o and #o > 0
+end
+
+local function none(o)
+  return not some(o)
+end
+
+M.shlex = {
+  whitespace = " \t\r\n",
+  whitespace_split = false,
+  quotes = [['"]],
+  escape = [[\]],
+  escapedquotes = '"',
+  state = " ",
+  pushback = {},
+  lineno = 1,
+  debug = 0,
+  token = "",
+  commenters = "#",
+  wordchars = "abcdfeghijklmnopqrstuvwxyz" .. "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_",
+}
+M.shlex.__index = M.shlex
+
+local sr = require("kulala.lib.shlex.stringreader")
+
+function M.shlex:create(str, posix, punctuation_chars)
+  local o = {}
+  setmetatable(o, M.shlex)
+
+  o.sr = sr(str or "")
+
+  if not posix then
+    o.eof = ""
+  end
+
+  o.posix = posix == true
+  if o.posix then
+    o.wordchars = o.wordchars
+      .. "ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ"
+      .. "ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ"
+  end
+
+  if punctuation_chars then
+    punctuation_chars = "();<>|&"
+  else
+    punctuation_chars = ""
+  end
+
+  o.punctuation_chars = punctuation_chars
+
+  if punctuation_chars then
+    o._pushback_chars = {}
+    o.wordchars = o.wordchars .. "~-./*?="
+    for i = 1, #o.punctuation_chars do
+      local c = o.punctuation_chars:sub(i, i)
+      o.wordchars:gsub(c, "", 1, true)
+    end
+  end
+
+  return o
+end
+
+function M.shlex:push_token(tok)
+  table.insert(self.pushback, tok)
+end
+
+function M.shlex:read_token()
+  local quoted = false
+  local escapedstate = " "
+  local nextchar
+
+  while true do
+    if some(self.punctuation_chars) and some(self._pushback_chars) then
+      nextchar = table.remove(self._pushback_chars)
+    else
+      nextchar = self.sr:read(1)
+    end
+
+    if nextchar == "\n" then
+      self.lineno = self.lineno + 1
+    end
+
+    if self.debug >= 3 then
+      print("shlex: in state '" .. (self.state or "nil") .. "' I see character: '" .. (nextchar or "nil") .. "'")
+    end
+
+    if none(self.state) then
+      self.token = ""
+      break
+    elseif self.state == " " then
+      if none(nextchar) then
+        self.state = nil
+        break
+      elseif self.whitespace:find(nextchar, 1, true) then
+        if self.debug >= 2 then
+          print("shlex: I see whitespace in whitespace state")
+        end
+        if some(self.token) or (self.posix and quoted) then
+          break
+        else
+          break
+        end
+      elseif self.commenters:find(nextchar, 1, true) then
+        self.sr:readline()
+        self.lineno = self.lineno + 1
+      elseif self.posix and self.escape:find(nextchar, 1, true) then
+        escapedstate = "a"
+        self.state = nextchar
+      elseif self.wordchars:find(nextchar, 1, true) then
+        self.token = nextchar
+        self.state = "a"
+      elseif self.punctuation_chars:find(nextchar, 1, true) then
+        self.token = nextchar
+        self.state = "c"
+      elseif self.quotes:find(nextchar, 1, true) then
+        if not self.posix then
+          self.token = nextchar
+        end
+        self.state = nextchar
+      elseif self.whitespace_split then
+        self.token = nextchar
+        self.state = "a"
+      else
+        self.token = nextchar
+        if some(self.token) or (self.posix and quoted) then
+          break
+        else
+          break
+        end
+      end
+    elseif self.quotes:find(self.state, 1, true) then
+      quoted = true
+      if none(nextchar) then
+        if self.debug >= 2 then
+          print("shlex: I see EOF in quotes state")
+        end
+        error("no closing quotation")
+      end
+      if nextchar == self.state then
+        if not self.posix then
+          self.token = self.token .. nextchar
+          self.state = " "
+          break
+        else
+          self.state = "a"
+        end
+      elseif self.posix and self.escape:find(nextchar, 1, true) and self.escapedquotes:find(self.state, 1, true) then
+        escapedstate = self.state
+        self.state = nextchar
+      else
+        self.token = self.token .. nextchar
+      end
+    elseif self.escape:find(self.state, 1, true) then
+      if none(nextchar) then
+        if self.debug >= 2 then
+          print("shlex: I see EOF in escape state")
+        end
+        error("no escaped character")
+      end
+      if self.quotes:find(escapedstate, 1, true) and nextchar ~= self.state and nextchar ~= escapedstate then
+        self.token = self.token .. self.state
+      end
+      self.token = self.token .. nextchar
+      self.state = escapedstate
+    elseif self.state == "a" or self.state == "c" then
+      if none(nextchar) then
+        self.state = nil
+        break
+      elseif self.whitespace:find(nextchar, 1, true) then
+        if self.debug >= 2 then
+          print("shlex: I see whitespace in word state")
+        end
+        self.state = " "
+        if some(self.token) or (self.posix and quoted) then
+          break
+        else
+          break
+        end
+      elseif self.commenters:find(nextchar, 1, true) then
+        self.sr:readline()
+        self.lineno = self.lineno + 1
+        if self.posix then
+          self.state = " "
+          if some(self.token) or (self.posix and quoted) then
+            break
+          else
+            break
+          end
+        end
+      elseif self.state == "c" then
+        if self.punctuation_chars:find(nextchar, 1, true) then
+          self.token = self.token .. nextchar
+        else
+          if not self.whitespace:find(nextchar, 1, true) then
+            table.insert(self._pushback_chars, nextchar)
+          end
+          self.state = " "
+          break
+        end
+      elseif self.posix and self.quotes:find(nextchar, 1, true) then
+        self.state = nextchar
+      elseif self.posix and self.escape:find(nextchar, 1, true) then
+        escapedstate = "a"
+        self.state = nextchar
+      elseif
+        self.wordchars:find(nextchar, 1, true)
+        or self.quotes:find(nextchar, 1, true)
+        or (self.whitespace_split and not self.punctuation_chars:find(nextchar, 1, true))
+      then
+        self.token = self.token .. nextchar
+      else
+        if some(self.punctuation_chars) then
+          table.insert(self._pushback_chars, nextchar)
+        else
+          table.insert(self.pushback, nextchar)
+        end
+        self.state = " "
+        if some(self.token) or (self.posix and quoted) then
+          break
+        else
+          break
+        end
+      end
+    end
+  end
+
+  local result = self.token
+  self.token = ""
+  if self.posix and not quoted and result == "" then
+    result = nil
+  end
+  if result and result:find("^%s*$") then
+    result = self:read_token()
+  end
+  if self.debug > 1 then
+    if result then
+      print("shlex: raw token=" .. result)
+    else
+      print("shlex: raw token=EOF")
+    end
+  end
+  return result
+end
+
+function M.shlex:next()
+  if some(self.pushback) then
+    return table.remove(self.pushback)
+  end
+  local raw = self:read_token()
+  return raw
+end
+
+function M.shlex:list()
+  local parts = {}
+  while true do
+    local next = self:next()
+    if next == self.eof or next == nil then
+      break
+    end
+    table.insert(parts, next)
+  end
+  return parts
+end
+
+setmetatable(M.shlex, {
+  __call = M.shlex.create,
+})
+
+function M.split(str, comments, posix)
+  if not str then
+    str = ""
+  end
+  if type(posix) == "nil" then
+    posix = true
+  end
+  local lex = M.shlex(str)
+  lex.posix = posix
+  if comments == false then
+    lex.commenters = ""
+  end
+  return lex:list()
+end
+
+function M.join(parts)
+  local ret = ""
+  for idx, part in ipairs(parts) do
+    ret = ret .. M.quote(part)
+    if idx ~= #parts then
+      ret = ret .. " "
+    end
+  end
+  return ret
+end
+
+M._unsafe = "^@%+=:,./-"
+
+function M.quote(s)
+  if none(s) then
+    return [['']]
+  end
+  local found = false
+  if s:find("%w") then
+    found = true
+  else
+    for i = 1, #s do
+      local c = s:sub(i, i)
+      if M._unsafe:find(c, 1, true) then
+        found = true
+        break
+      end
+    end
+  end
+  if not found then
+    return s
+  end
+  return "'" .. s:gsub("'", "'\"'\"'") .. "'"
+end
+
+return M